BULLETIN OF TIM, SOUTHERN CALIFORNIA ACAD E M Y O I SCIENC IS Voi.umi; 72 .Mini. 7, 1973 Nl Mill I' I NEW TAXA OF BRACHYURAN CRABS FROM DIM' WATER OFF WESTERN PI Rl AND COSTA RICA John S. GARTH 1 Abstract: Five new species and one new genus of brachyuran crabs obtained by 1 M del Solar and E. Fernandez-B. are described and illustrated. Of these, Homolodromia roberlsi, Acanthocarpus delsolari, Pilumnus fernandezi, and Trizocarciniu peruvianus are most closely re- lated to western Atlantic deep-water species, whereas. Delsolaria enriquei, a new genus and spe- cies, is a west American endemic. The family Homolodiomiidae and ihe genera Homolodromia and Acanthocarpus are reported for the first time from the eastern Pacific. Il is postulated that the analogous pairs of deep-water Amphi-american species have been separated since free communication existed at or near the depths at which they presently occur. I he Bolivar Trench which extends across northern South America is suggested as the probable Miocene or earlier connection. Through the efforts of Enrique M. del Solar-C. technical adviser to IMARPE (Instituto del Mar del Peru), careinological collections from a hitherto untapped source have lately found their way into museums in the United States and western Europe, among them the Allan Hancock Foundation (AHF), Los Angeles, the U.S. Na- tional Museum of Natural History (USNM), Washington, and the Royal Netherlands Museum (RNM), Leiden. These come from deep waters off Peru, and are the by-product of a search for edible shrimp and other fisheries products con- ducted by the research vessels "Wiracocha," "Challua japic," and "SNP-1" under the direction of del Solar. Independent probing of deep waters off western Costa Rica by Hno. Eduardo Fernandez-B., Colegio de La Salle, San Jose, has similarly enriched the collections of the U.S. National Museum. Not only have a number of the brachyuran species proven to be new to science, but repre- sented among them are genera and families not previously known to inhabit the eastern Pacific. Four of the new species described herein have already been mentioned in Peruvian journals (del Solar, Blancas. and Mayta. 1970: del Solar. 1972) with identifications to genus only, and three have been illustrated (Chirichigno, 1970), but without specific names. Since the genera under which they were first reported may differ from the ones used here, and since the published illustrations are sometimes insufficient for species identifica- tion, citations to the above are given for clarifica- tion only, and are not intended to establish priority for the species in question, which dates solely from this publication. This paper is Allan Hancock Foundation Contribution No. 343. SYSTEMATIC ACCOUNT Family HOMOLODROMIIDAE Homolodromia robertsi. new specie^ Figure 1. A-F Type: Female, holotype, AHF No. 719. from off Peru. lat. 03°48.5' S. long. 81°18.4' w . 800 m. 11 January 1971. mud bottom. E. M. del Solar, collector (Orig. No. B-260). Ovigerous female, paratype. USNM No. 141570. from off Peru. lat. 07 ; 59' S. long. S0 C 22' \V. 800 m. 26 November 1971. hard bottom. Trawler "Challua japic." E. M. del Solar, collector (Orig. No. B-376). Measurements (all in millimeters): Female holo- type: length, including rostrum. 42.5. width length of rostrum. 4.0. width of rostrum. 7.5, cheliped 1 Allan Hancock Foundation. Universitj ern California. Los Angeles. Califorri Hllllll\ sol I III K\ CM NORMA ACADEMY OF SCIENCES VOLUME 72 1973 Nl.W BRACHYURAN CRABS IKOM EASTERN PACIFH (coxa-ischium-merus, 35.4, carpus-propodus, 37.8), 73.2, chela, 28.0, dactyl, 13.5. heighl "i palm, 7.2, walking legs, from firsl to last, '«, 90, 36, and 39. Diagnosis', Rostral and exorbital spines short .mil subequal, the latter more forwardly than outwardly directed. Median and lateral portions of cervical su- ture continuous. Carapace, chelipeds, and walking legs spinulous. Description: Carapace lliiek, swollen, pilose, sur- face spinulous, punctate, divided by cervical and branchial sutures into unequal thirds. Posterior branchial regions dilated, limited anteriorly by bran- chial furrow; anterior branchial regions similarly de- limited from gastric and hepatic regions by cervical furrow. Front with two stout, triangular horns reach- ing extremity of third article of antenna, outer margins sloping toward a similar' and forward-directed exor- bital spine. Rostral horns and outer orbital spines straight, tubular, the former flattened beneath, the latter spinulous externally. Eyestalks thick, short, cylindrical, two spinules at base; cornea terminal, of diameter equal to eyestalk, color yellowish brown. Supraorbital margin smooth, with a narrow raised border bearing one or two spinules. Lateral margins spinulous, constricted by the aforementioned grooves. Basal antennal article with concealed green-gland opening internally, three or four spinules externally, the outer two in line; second article with two spinules in line externally, a cluster of spinules anteroin- ternally, and a large spine anteroexternally; third (first flagellar) article with a subdistal spinule ex- ternally and two spinides in line internally. Outer maxilliped densely haired, especially along internal margin, merus broader than ischium, arcuate outer margin spinulous; palp coarse, cylindrical. Chelipeds of female equal, pilose, margins of merus, carpus, and manus spinulous, prehensile margins of fingers dentate, dactylus fitting into a fork-tipped propodus. First two pairs of ambulatory legs long, slender, cylindrical, pilose, spinulous. dactyli long and strongly curved. Last two pairs of legs short, elevated, chelate, chela of third leg directed backward, that of the fourth leg directed forward, dactyl fitting a fork formed by two or more propodal spines. Female abdomen with seven free segments, seventh segment cordiform. longer than preceding six. The male of the species is unknown. Remarks: Homolodromia robertsi differs from the western Atlantic Homolodromia paradoxa A. Milne-Edwards, 1880, as follows: shorter rostral and exorbital spines, the latter more forwardly than outwardly directed; the median portion of the cervical suture continuous with ilic lateral poi lions; the carapace and the wall ing leg Spinulous; and in having the legs id the last two pair-. thortCI although this may he a chaiactei associated With the female sex. I he new specie, differs from the Last African Homolodromia bouvierl Doflcin, 1904, in having the carapace broader posteriorly, the furrows more clearly discernible, giving it a lightly laced appearance, the rostral and exorbital spines are straight instead of incurving (cf, Doflein, 1904, text-fig, I ). the eyestalks shmi and thick, the cornea pigmented, the outer maxilliped thicker, the antennal peduncle and walking legs more spinulous, including the meri and propodi, which in //. bouvieri are without spinules. I take pleasure in naming this new species lor Henry B. Roberts, Senior Museum Specialist, U.S. National Museum of Natural History. Washing- ton, D.C., whose assistance in preparing its description is gratefully acknowledged. Family CALAPPIDAE Acanthocarpus delsolari, new species Figure 2, A-F Mursia sp. Chiriehigno, 1970. p. 41. text-fig. 85. Type: Holotype, female. AHF No. 703, from near Banco de Mancora. off Peru. lat. 03"43' S. long. 81°03' W. 250 m. mud bottom. 30 August 1970. E. M. del Solar, collector (Orig. No. B-204). Measurements (in millimeters): Female holotype: length. 25.3. breadth, 27.6. frontal width. 3.4. fronto- orbital width, 10.8, length of meral spine. 11.0. length of chela, 17.9, dactyl. 7.8. height of palm. 12.1. Over- all width, including meral spines. 60.5. Diagnosis: Carapace ovate, posterolateral spine of moderate length. Two meral spines, the inferior much the longer. Posterolateral margin non- tuberculate. A tooth on posterior margin and a conical tubercle on either side of sternal plastron. Tubercles of carapace arranged in longitudinal rows, most prominent posteriorly and laterally. Description: Carapace regularly convex, widest opposite middle, surface uneven, protuberances ar- ranged in five longitudinal rows of which one is median, tubercles of lateral ridges increasingly prominent posteriorly, tending to coalesce, the outer- most protruding beyond posterolateral margin, which Figure 1. Homolodromia robertsi. new species, female holotype: A. dorsal view: B. ventral view of frontal region; C, outer view of right chela; D. tip of left third walking leg: E. right outer maxilliped; F. abdomen. 81 III ll\ so/ lllll<\ < ILIFORNIA ACADEMY Ol SCIENCES VOLUME 72 10 mm Figure 2. Acanthocarpus dclsolari, new species, female holotype: A, dorsal view; B, frontal view, showing suborbital tubercles; C, outer view of right cheliped; D, inner view of same, showing stridulating ridge; E, abdomen and sternal plastron; F, left outer maxilliped. 197.1 NEW BRA( I1YIIKAN (KAHS I ROM EASTERN I'M UK bears a moderately loll)/,, conical, more lalerally llian posteriorly directed spine. Surface covered with mi mile granules and pnnclae. Iron! moderately wide, trilobate, separated from orbil by a shallow notch. Orbits large, margins hairy, superior fissure ob solcsccnl. Anterolateral margin wilh lour obscure lubcrculiform teeth, followed by three smaller tuber- cles :ii widest pari of carapace, Posterior margin arcuate, bearing a large loolh at middle and a smaller looth on either side. Spine at ouicr angle of merus of chelipcd approxi- mately two-fifths width of carapace; superior spine approximately one-fifth length of inferior. Hand with a seven-toothed crest above and an oblique, five- toothed cresl on outer surface extending from base of daclylus to posleroinferior angle; posterior looth largest, conical, separated, from oilier teeth by a con- siderable interval. Six or seven scattered tubercles forming an irregular line between upper and lower crests. Stridulating ridge on inner surface of manus composed of about 47 closely placed, oblique Striae, which engage a series of coarser oblique tubercles on the suborbital margin to produce Ihe vibratory grating described for Acanthocarpus bispinosus by Rathbun (1937:224). Outer maxilliped truncate-triangular, inner margin of ischium denticulate, a diagonal row of setae cross- ing exognath and merus of endognath. Ambulatory legs naked, unarmed, surface smooth and polished, carpi ridged, propodi laterally com- pressed, dactyli long, vertically compressed, incurving. A conical tubercle on either side of first sternite. The male of Ihe species is unknown. Color in alcohol: Carapace reddish orange, deepest on anterior portion. A spot of orange surrounding each stridulating ridge. Remarks: The proposed new species appears to be more closely related to Acanthocarpus alexandri Stimpson, 1871 (Massachusetts to Windward Is- lands), type species of the genus, than to A. bispinosus A. Milne-Edwards, 1880 (Florida Straits to Windward Islands). Acanthocarpus delsolari resembles the former in having the cara- pace narrowing posteriorly; two meral spines, the inferior the larger; a tooth on the posterior margin; and a pair of tubercles on the sternal plastron. Furthermore, while the postlateral spine is longer than in alexandri, it is not as long as in bispinosus, nor as laterally directed. Acanthocarpus delsolari differs from both in having prominent branchial tuberculate ridges, the outermost actually over- hanging the posterolateral margin. I take pleasure in naming this species for E. M. del Solar, of Lima, Peru, who recognized it as belonging to a genus hitherto unreported from the American west coast. I i ly MAUI) M Delsolaria, new genus Type species: Delsolaria enrlquel, new species Description: Carapace ovati triangulai regions ele- vated and tnbcrculatcd, postcrioi margin lamellate Rostrum consisting of two flattened horn small, a fissure above and below, Ihe lower one open. Preorbital spine and postorbital cup closely approxi mated, intercalary spine absent. Basal antennal article broadened basally. forming flooi ol orbit, a spine at antcroextcrnal angle. Maxilliped with cx- Ognath as wide as cmlotrn.il h proximally. ischium widening dislally, merus truncate distally, expanded anlcrocxtcrnally, notched at anlcrointcrnal angli ( helipeds of female slightly more robust lhan walking legs, manus compressed and carinaled, fingers pointed. Walking legs short and stout, carpi luberculatcd. Abdomen of female seven-segmented: male sex unknown. Relationship: The new genus appears to belong among those genera of the subfamily Pisinae in which the supraocular eave is in close contact with the postocular cup. However, the remarkable broadening of the basal antennal article suggests affinities with certain genera of the subfamily Majinae as well. Final placement and inclusion in a key must await the discovery of a male specimen. Delsolaria enriquei, new species Figure 3. A-F Type: Female, holotype. AHF No. 704. from north side of Banco de Mancora, Peru, 35 m. gravel, 9 December 1970. E. M. del Solar, collector (Orig. No. B-256). Measurements (in millimeters): Female holotype: length, including rostrum. 37.7. rostrum. 6.2. width at level of branchial spines, 29.6, at level of postero- lateral margin. 26.4. cheliped (ischium-merus 1 2.7. carpus-propodus 17.0). 27.7. chela. 13.8, dactyl, 6.6. height of palm, 4.7. Diagnosis: Gastric, cardiac, and branchial regions swollen and tuberculate. Lateral branchial tubercle prominent. Rostral, preorbital. and antennal spines of like size and sharpness. Maxilliped distally fringed with clavate setae. Description: Carapace ovate-triangular, one and one-quarter times longer than wide, highly convex medianly and laterally, elevations studded with rounded tubercles, depressions smooth but micr ically punctate, sides declivitous, posterior margin lamellate. Front bifid, horns sharp, cleft shallow. U-shaped, sides parallel or slightly concave, a double row of curled setae on each: frontal, antennal. and preorbital spines of comparable size and sharpness. BJ /// //\ SOI //// A'\ < AL1F0RN1 I iCADBMY OF SCIENCES VOLUME 72 5 mm Figure 3. Deholaria cnriquei, new species, female holotype: A, dorsal view; B, right lateral view; C, left chela, outer view; D, right outer maxilliped; E, ventral view of frontal region; F, abdomen. /^ de su distribuci6n geografiea. Inf. Inst. Mar Peru